High-strength and high-conductivity copper-aluminum-copper composite materials and their preparation process

Abstract

The purpose of this invention is to disclose a high-strength, high-conductivity copper-aluminum-copper composite material and its preparation process, relating to the field of metal composite material technology. The copper-aluminum-copper composite material comprises, from top to bottom, a first high-strength copper alloy layer, a first aluminum layer, a second aluminum layer, a third aluminum layer, and a second high-strength copper alloy layer. The thicknesses of the first high-strength copper alloy layer, the first aluminum layer, the second aluminum layer, the third aluminum layer, and the second high-strength copper alloy layer are (0.2-0.3):(0.05-0.07):(0.5-0.7):(0.05- 0.07): (0.2-0.3); Beneficial effects: The first and third aluminum layers are made of 8011 aluminum alloy or 1060 aluminum alloy, which have high wettability with the first high-strength copper alloy layer and high casting-rolled composite strength; the second aluminum layer is made of 7A52 aluminum alloy or 6013 aluminum alloy, which has the characteristics of being lightweight but high-strength. It is hot-rolled and composited between the first aluminum layer and the third aluminum layer, so that a high-strength composite interface is formed between the first aluminum layer, the second aluminum layer and the third aluminum layer, forming a high-strength and high-conductivity copper-aluminum-copper composite material.

Description

Technical Field

[0001] This invention relates to the field of metal composite materials technology, and in particular to a high-strength, high-conductivity copper-aluminum-copper composite material and its preparation process. Background Technology

[0002] In fields such as aerospace, transportation, electronic communications, marine engineering, and special equipment, where high strength and high conductivity are required for conductor materials, copper-aluminum composite materials are a good choice.

[0003] Currently, to achieve a tensile strength of 350 MPa for copper-aluminum composite materials, the copper layer needs to account for more than 50% of the total thickness. However, an excessively large copper layer results in a mediocre weight reduction effect, hindering the promotion of high-strength, high-conductivity copper-aluminum composite materials.

[0004] Therefore, it is necessary to develop a high-strength, high-conductivity copper-aluminum-copper composite material and its preparation process to overcome the above-mentioned defects. Summary of the Invention

[0005] The purpose of this invention is to disclose a high-strength, high-conductivity copper-aluminum-copper composite material and its preparation process.

[0006] The first objective of this invention is to provide a high-strength, high-conductivity copper-aluminum-copper composite material.

[0007] The second objective of this invention is to provide a process for preparing high-strength, high-conductivity copper-aluminum-copper composite materials.

[0008] To achieve the first objective mentioned above, this invention provides a high-strength, high-conductivity copper-aluminum-copper composite material. The copper-aluminum-copper composite material comprises, from top to bottom, a first high-strength copper alloy layer, a first aluminum layer, a second aluminum layer, a third aluminum layer, and a second high-strength copper alloy layer. The thicknesses of the first high-strength copper alloy layer, the first aluminum layer, the second aluminum layer, the third aluminum layer, and the second high-strength copper alloy layer are (0.2-0.3):(0.05-0.07):(0.5-0.7):(0.05-0.07):(0.2-0.3).

[0009] The first high-strength copper alloy layer is either T2 copper alloy or C18150 copper alloy;

[0010] Both the first aluminum layer and the third aluminum layer are made of 8011 aluminum alloy or 1060 aluminum alloy;

[0011] The material of the second aluminum layer is 7A52 aluminum alloy or 6013 aluminum alloy.

[0012] Preferably, the tensile strength of the copper-aluminum-copper composite material is not less than 360 MPa, and the electrical conductivity of the copper-aluminum-copper composite material is not less than 70% IACS.

[0013] Based on the same inventive principle, and to achieve the first inventive objective mentioned above, this invention provides a process for preparing high-strength, high-conductivity copper-aluminum-copper composite materials, comprising the following steps:

[0014] The high-strength copper alloy strip is heated to a first temperature, which is 100℃-150℃, and the high-strength copper alloy strip is T2 copper alloy or C18150 copper alloy.

[0015] The first aluminum alloy is liquefied and heated to a second temperature to obtain a liquid first aluminum alloy. The second temperature is 30°C-60°C higher than the melting point of the first aluminum alloy. The material of the first aluminum alloy is 8011 aluminum alloy or 1060 aluminum alloy.

[0016] The liquid first aluminum alloy and the high-strength copper alloy strip are continuously cast and rolled. The high-strength copper alloy strip is heated from the first temperature to a third temperature, which is 30°C-60°C higher than the cell transformation temperature of the high-strength copper alloy strip, to obtain a copper-aluminum composite substrate.

[0017] A copper-aluminum-copper composite material is obtained by simultaneously hot-rolling copper-aluminum composite substrate on both sides of a high-strength aluminum alloy strip. The high-strength aluminum alloy strip is made of 7A52 aluminum alloy or 6013 aluminum alloy.

[0018] Preferably, the continuous casting and rolling speed is 0.5 m / s to 3 m / s.

[0019] Preferably, the continuous casting and rolling speed is 1m / s-2m / s.

[0020] Preferably, the rolling force of the continuous casting and rolling is 1000t-2000t.

[0021] Preferably, the hot-rolled composite temperature is 480℃-520℃, and the hot-rolled composite rolling force is 100t-1200t.

[0022] Preferably, the reduction rate of the hot-rolled composite is 10%-20%.

[0023] Preferably, the tensile strength of the copper-aluminum-copper composite material is not less than 360 MPa, and the electrical conductivity of the copper-aluminum-copper composite material is not less than 70% IACS.

[0024] Preferably, the high-strength aluminum alloy strip and the two layers of the composite copper-aluminum composite substrate are simultaneously fed into a temperature control furnace. The temperature control furnace is equipped with a protective atmosphere, which includes 20%-30% hydrogen and the remainder is nitrogen.

[0025] Compared with the prior art, the beneficial effects of the present invention are:

[0026] (1) The first aluminum layer and the third aluminum layer of the present invention are both made of 8011 aluminum alloy or 1060 aluminum alloy. The 8011 aluminum alloy or 1060 aluminum alloy has high wettability with the first high-strength copper alloy layer and high casting-rolled composite strength. The second aluminum layer is made of 7A52 aluminum alloy or 6013 aluminum alloy, which has the characteristics of being lightweight but high-strength. It is hot-rolled and composited between the first aluminum layer and the third aluminum layer, so that a high-strength composite interface is formed between the first aluminum layer, the second aluminum layer and the third aluminum layer, forming a high-strength and high-conductivity copper-aluminum-copper composite material with a tensile strength of not less than 360MPa and an electrical conductivity of not less than 70%IACS.

[0027] (2) The first aluminum layer and the third aluminum layer of the present invention contain Si. The role of Si is to increase the wettability between aluminum and copper, ensure the wettability between the high wettability aluminum alloy liquid and the high strength copper alloy strip, and increase the peel force between the copper-aluminum composite materials. The first temperature is the initial temperature of the high strength copper alloy strip. When the liquid first aluminum alloy and the high strength copper alloy strip with the first temperature are continuously cast and rolled, the heat of the liquid first aluminum alloy will be transferred and diffused to the high strength copper alloy strip, and the temperature of the high strength copper alloy strip will reach the third temperature. The third temperature is 30°C-60°C higher than the cell transformation temperature of the high strength copper alloy strip. By controlling the first temperature, the second temperature and the third temperature, the composite strength between the copper-aluminum composite materials is further increased. Attached Figure Description

[0028] Figure 1 This is a cross-sectional view of the high-strength, high-conductivity copper-aluminum-copper composite material of the present invention.

[0029] Figure 2 This is a process flow diagram for preparing the high-strength, high-conductivity copper-aluminum-copper composite material of the present invention.

[0030] Figure 3 This is an electron microscope image of the copper-aluminum casting-rolling interface of the present invention.

[0031] Figure 4 This is an elemental line scan diagram of the copper-aluminum casting-rolling interface of the present invention.

[0032] Figure 5 This is an electron microscope image of the interface between the first aluminum layer and the second aluminum layer of the present invention.

[0033] Among them, 1. First high-strength copper alloy layer; 2. First aluminum layer; 3. Second aluminum layer; 4. Third aluminum layer; 5. Second high-strength copper alloy layer. Detailed Implementation

[0034] The present invention will now be described in detail with reference to the embodiments shown in the accompanying drawings. However, it should be noted that these embodiments are not intended to limit the present invention. Equivalent changes or substitutions in function, method, or structure made by those skilled in the art based on these embodiments are all within the scope of protection of the present invention.

[0035] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "top," "bottom," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0036] Example 1

[0037] See Figure 1 This embodiment provides a high-strength, high-conductivity copper-aluminum-copper composite material. The copper-aluminum-copper composite material comprises, from top to bottom, a first high-strength copper alloy layer 1, a first aluminum layer 2, a second aluminum layer 3, a third aluminum layer 4, and a second high-strength copper alloy layer 5. The thicknesses of the first high-strength copper alloy layer 1, the first aluminum layer 2, the second aluminum layer 3, the third aluminum layer 4, and the second high-strength copper alloy layer 5 are (0.2-0.3): (0.05-0.07): (0.5-0.7): (0.05-0.07): (0.2-0.3). The first high-strength copper alloy layer 1 is a T2 copper alloy or a C18150 copper alloy. The first aluminum layer 2 and the third aluminum layer 4 are both made of 8011 aluminum alloy or 1060 aluminum alloy. The second aluminum layer 3 is made of 7A52 aluminum alloy or 6013 aluminum alloy.

[0038] Specifically, see Figure 1 The preferred thickness ratio of the first high-strength copper alloy layer 1: the first aluminum layer 2: the second aluminum layer 3: the third aluminum layer 4: the second high-strength copper alloy layer 5 is 0.2:0.05:0.7:0.05:0.2. The sum of the thicknesses of the first high-strength copper alloy layer 1 and the second high-strength copper alloy layer 5 accounts for 33.3% of the total thickness of the copper-aluminum-copper composite material, and the sum of the thicknesses of the first aluminum layer 2, the second aluminum layer 3, and the third aluminum layer 4 accounts for 66.7% of the total thickness. Under this thickness ratio, the tensile strength of the copper-aluminum-copper composite material is not less than 360 MPa, and the electrical conductivity of the copper-aluminum-copper composite material is not less than 70% IACS, achieving high strength and high electrical conductivity. At the same time, the density of the copper-aluminum-copper composite material is significantly reduced compared to pure copper, achieving significant weight reduction.

[0039] Example 2

[0040] See Figure 1 A process for preparing a high-strength, high-conductivity copper-aluminum-copper composite material includes the following steps:

[0041] S1: The high-strength copper alloy strip is heated to a first temperature, which is 100℃-150℃. The high-strength copper alloy strip is either T2 copper alloy or C18150 copper alloy. Specifically, the first temperature is the initial temperature of the high-strength copper alloy strip, preferably 130℃. This initial temperature ensures that the composite temperature with the first aluminum alloy meets the requirements during subsequent continuous rolling, thereby ensuring the composite strength. The high-strength copper alloy strip is heated to the first temperature by a copper strip auxiliary heating device, that is, the high-strength copper alloy strip is heated to the first temperature after passing through the auxiliary heating device.

[0042] S2: The first aluminum alloy is liquefied and heated to a second temperature to obtain a liquid first aluminum alloy. The second temperature is 30°C-60°C higher than the melting point of the first aluminum alloy. The first aluminum alloy is made of 8011 aluminum alloy or 1060 aluminum alloy. Specifically, the role of Si in the first aluminum alloy is to increase the wettability between aluminum and copper, ensuring the wettability between the first aluminum alloy and the high-strength copper alloy strip, and increasing the composite strength between the copper-aluminum composite material. In addition, the second temperature is 30°C-60°C higher than the melting point of the first aluminum alloy, preferably 35°C higher, so that the first aluminum alloy can carry sufficient heat.

[0043] S3: The liquid first aluminum alloy and the high-strength copper alloy strip are continuously cast and rolled. The high-strength copper alloy strip is heated from the first temperature to a third temperature, which is 30°C-60°C higher than the cell transformation temperature of the high-strength copper alloy strip, to obtain a copper-aluminum composite substrate. Specifically, the liquid first aluminum alloy is transported to the casting and rolling zone via a guide channel and a casting nozzle. The use of the first aluminum alloy ensures high wettability between copper and aluminum. The continuous casting and rolling speed is 0.5 m / s-3 m / s, preferably 1 m / s-2 m / s. The rolling force is 1000 t-2000 t, preferably 2000 t. To further ensure the composite strength between copper and aluminum, the first temperature is the initial temperature of the high-strength copper alloy strip, preferably 130°C. During continuous casting and rolling of the first aluminum alloy and the high-strength copper alloy strip at the first temperature, the heat from the first aluminum alloy is transferred and diffused to the high-strength copper alloy strip, raising its temperature to a third temperature. This third temperature is 30°C-60°C higher than the cell transformation temperature of the high-strength copper alloy strip, preferably 400°C, and the third temperature is preferably 430°C. By controlling the first, second, and third temperatures, the composite strength between the copper and aluminum composite materials is further increased.

[0044] S4: A copper-aluminum composite material is obtained by simultaneously hot-rolling a copper-aluminum composite substrate on both sides of a high-strength aluminum alloy strip. The high-strength aluminum alloy strip is made of 7A52 aluminum alloy or 6013 aluminum alloy. Specifically, the hot-rolling temperature is 480℃-520℃, preferably 500℃; the rolling force is 100t-1200t, preferably 1000t; and the reduction rate is 10%-20%, preferably 15%. 7A52 aluminum alloy or 6013 aluminum alloy is lightweight and has high strength. However, 7A52 aluminum alloy or 6013 aluminum alloy contains a relatively high amount of zinc. The wettability between 7A52 aluminum alloy or 6013 aluminum alloy and the high-strength copper alloy strip is poor, making direct bonding difficult or resulting in insufficient composite strength. To meet the usage requirements, this embodiment incorporates a first aluminum alloy between a high-strength aluminum alloy strip and a high-strength copper alloy strip. The first aluminum alloy exhibits good wettability with the high-strength aluminum alloy strip, and both the first aluminum alloy and the high-strength aluminum alloy strip are primarily composed of aluminum. Furthermore, the first aluminum alloy and the high-strength aluminum alloy strip exhibit even better wettability. This embodiment achieves the preparation of a high-strength, high-conductivity composite material through a combination of continuous casting and hot rolling processes. This results in a tensile strength of not less than 360 MPa and an electrical conductivity of not less than 70% IACS for the copper-aluminum-copper composite material.

[0045] It should be noted that before hot rolling composite, the high-strength aluminum alloy strip and the two layers of the composite copper-aluminum composite substrate are simultaneously fed into a layer temperature control furnace. The layer temperature control furnace is equipped with a protective atmosphere, which includes 20%-30% hydrogen and the remainder nitrogen. The protective atmosphere ensures the brightness of the high-strength aluminum alloy strip and the two layers of the composite copper-aluminum composite substrate, prevents their oxidation, and provides a basis for ensuring the quality of the composite interface.

[0046] Through steps S1 to S4, the high-strength, high-conductivity copper-aluminum-copper composite material described in Example 1 was prepared. The tensile strength of the copper-aluminum-copper composite material is not less than 360 MPa, and the electrical conductivity of the copper-aluminum-copper composite material is not less than 70% IACS. See the electron microscope image of the interface between the first high-strength copper alloy layer 1 (C18150 copper alloy) and the first aluminum layer 2 (1060 aluminum alloy). Figure 3 As can be seen, the composite material prepared by casting and rolling has a smooth interface and good bonding. SEM observation of the composite material of the first high-strength copper alloy layer 1 and the first aluminum layer 2 shows that there are no obvious pores or impurities at the interface, the diffusion-induced Kirkendall effect is weak, and an interface layer of approximately 0.8 μm is formed. The interface lines on both sides of the copper and aluminum are smooth, indicating a good metallurgical state, which is beneficial for subsequent rolling and heat treatment. (See also...) Figure 4 , Figure 4 It is an element line scan diagram display. Figure 3 At point 1, the atomic ratio of aluminum to copper atoms is approximately 4:9. Figure 3At point 2, the atomic ratio of aluminum to copper atoms is approximately 2:1. From the copper side to the aluminum side, the copper content gradually decreases while the aluminum content increases. Based on this analysis, the interface can be determined to consist of two layers: the layer closer to copper is an Al4Cu9 interface compound, and the layer closer to aluminum is an Al2Cu interface compound. (See also...) Figure 5 , Figure 5 This is an electron microscope image of the interface between the first aluminum layer 2 and the second aluminum layer 3. The first aluminum layer 2 is taken as an example of 1060 aluminum alloy, and the second aluminum layer 3 is taken as an example of 7A52 aluminum alloy. Figure 5 The absence of a clear interface between the first aluminum layer 2 and the second aluminum layer 3 indicates a strong bond between them.

[0047] See Table 1, which is a table of performance parameters for copper-aluminum composite materials.

[0048] Table 1 Performance parameters of copper-aluminum composite materials

[0049]

[0050] The test results in Table 1 show that the effects on the tensile strength (MPa) and electrical conductivity of copper-aluminum composite materials are mainly reflected in the following aspects: (1) The first temperature is the key factor. The combination of the second temperature and the first temperature ensures the third temperature, thereby ensuring the composite interface and tensile strength; (2) The rolling force plays an auxiliary role in tensile strength (MPa); (3) The tensile strength (MPa) and electrical conductivity of copper alloy and aluminum alloy models are provided with basic guarantees.

Claims

1. A preparation process for high-strength, high-conductivity copper-aluminum-copper composite materials, characterized in that, Includes the following steps: The copper alloy strip is heated to a first temperature, which is 100℃-150℃, and the copper alloy strip is C18150 copper alloy. The aluminum alloy is liquefied and heated to a second temperature to obtain a liquid first aluminum alloy. The second temperature is 30°C-60°C higher than the melting point of the first aluminum alloy. The material of the first aluminum alloy is 8011 aluminum alloy or 1060 aluminum alloy. The liquid first aluminum alloy and the copper alloy strip are continuously cast and rolled, and the copper alloy strip is heated from the first temperature to the third temperature, which is 30°C-60°C higher than the cell transformation temperature of the copper alloy strip, to obtain a copper-aluminum composite substrate. A copper-aluminum-copper composite material is obtained by simultaneously hot-rolling copper-aluminum composite substrates on both sides of a high-strength aluminum alloy strip. The high-strength aluminum alloy strip is made of 7A52 aluminum alloy or 6013 aluminum alloy. The copper-aluminum-copper composite material comprises, from top to bottom, a first high-strength copper alloy layer, a first aluminum layer, a second aluminum layer, a third aluminum layer, and a second high-strength copper alloy layer. The ratio of the thickness of the first high-strength copper alloy layer to the thickness of the first aluminum layer to the thickness of the second aluminum layer to the thickness of the third aluminum layer to the thickness of the second high-strength copper alloy layer is (0.2-0.3):(0.05-0.07):(0.5-0.7):(0.05-0.07):(0.2-0.3). The tensile strength of the copper-aluminum-copper composite material is not less than 360 MPa, and the electrical conductivity of the copper-aluminum-copper composite material is not less than 70% IACS.

2. The preparation process of the high-strength, high-conductivity copper-aluminum-copper composite material as described in claim 1, characterized in that, The continuous casting and rolling speed is 0.5 m / s to 3 m / s.

3. The preparation process of high-strength, high-conductivity copper-aluminum-copper composite material as described in claim 2, characterized in that, The continuous casting and rolling speed is 1m / s-2m / s.

4. The preparation process of the high-strength, high-conductivity copper-aluminum-copper composite material as described in claim 1, characterized in that, The hot-rolled composite temperature is 480℃-520℃.

5. The preparation process of the high-strength, high-conductivity copper-aluminum-copper composite material as described in claim 4, characterized in that, The reduction rate of the hot-rolled composite is 10%-20%.

6. The preparation process of the high-strength, high-conductivity copper-aluminum-copper composite material as described in claim 1, characterized in that, Before hot rolling composite, the high-strength aluminum alloy strip and the two layers of copper-aluminum composite substrate are simultaneously fed into a layer temperature control furnace, which is equipped with a protective atmosphere.

7. A high-strength, high-conductivity copper-aluminum-copper composite material, characterized in that, It is prepared by the high-strength, high-conductivity copper-aluminum-copper composite material preparation process according to any one of claims 1-6.

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